Chucking system for nano-manufacturing

ABSTRACT

The present invention is directed towards a chucking system, including, inter alia, a body having a surface with a pin extending therefrom having a throughway defined therein, and a land surrounding the protrusions defining a channel between the pin and the land. In a further embodiment, the body comprises a plurality of protrusions.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a divisional patent application of U.S.patent application Ser. No. 11/047,499, filed Jan. 31, 2005, entitled“Method of Retaining a Substrate to a Wafer Chuck”, naming inventorsByung-Jin Choi, Anshuman Cherala and Daniel A. Babbs, now U.S. Pat. No.7,636,999, issued on Dec. 29, 2009; U.S. patent application Ser. No.11/108,208, filed Apr. 18, 2005 is a division of the presentapplication, entitled “Methods of Separating a Mold from a SolidifiedLayer Disposed on a Substrate,” naming inventors Byung-Jin Choi,Anshuman Cherala, Yeong-jun Choi, Mario J. Meissl, Sidlgata V.Sreenivasan, Norman E. Schumaker, Ian M. McMackin and Xiaoming Lu, nowU.S. Pat. No. 7,635,445, issued on Dec. 22, 2009; U.S. patentapplication Ser. No. 11/690,480, filed Mar. 23, 2007 is a continuationin part of the present application, entitled “Chucking System Comprisingan Array of Fluid Chambers”, now U.S. Pat. No. 7,635,263, issued on Dec.12, 2009.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

The U.S. Government has a paid-up license in this invention and theright in limited circumstances to require the patent owner to licenseothers on reasonable terms as provided by the terms of N66001-01-1-8964and N66001-02-C-8011 awarded by the Defense Advanced Research ProjectsAgency (DARPA).

BACKGROUND OF THE INVENTION

The field of the invention relates generally to nano-fabrication ofstructures. More particularly, the present invention is directed to achucking system to facilitate separating a template from a solidifiedlayer disposed on a substrate in an imprint lithography process.

Nano-fabrication involves the fabrication of very small structures,e.g., having features on the order of nano-meters or smaller. One areain which nano-fabrication has had a sizeable impact is in the processingof integrated circuits. As the semiconductor processing industrycontinues to strive for larger production yields while increasing thecircuits per unit area formed on a substrate, nano-fabrication becomesincreasingly important. Nano-fabrication provides greater processcontrol while allowing increased reduction of the minimum featuredimension of the structures formed. Other areas of development in whichnano-fabrication has been employed include biotechnology, opticaltechnology, mechanical systems and the like.

An exemplary nano-fabrication technique is commonly referred to asimprint lithography. Exemplary imprint lithographic processes aredescribed in detail in numerous publications, such as United Statespublished patent application 2004/0065976, filed as U.S. patentapplication Ser. No. 10/264,960, entitled, “Method and a Mold to ArrangeFeatures on a Substrate to Replicate Features having Minimal DimensionalVariability”; United States published patent application 2004/0065252,filed as U.S. patent application Ser. No. 10/264,926, entitled “Methodof Forming a Layer on a Substrate to Facilitate Fabrication of MetrologyStandards”; and United States published patent application 2004/0046271,filed as U.S. patent application Ser. No. 10/235,314, entitled“Functional Patterning Material for Imprint Lithography Processes,” allof which are assigned to the assignee of the present invention.

The fundamental imprint lithography technique disclosed in each of theaforementioned United States published patent applications includesformation of a relief pattern in a polymerizable layer and transferringa pattern corresponding to the relief pattern into an underlyingsubstrate. To that end, a template is employed spaced-apart from thesubstrate with a formable liquid present between the template and thesubstrate. The liquid is solidified to form a solidified layer that hasa pattern recorded therein that is conforming to a shape of the surfaceof the template in contact with the liquid. The template is separatedfrom the solidified layer such that the template and the substrate arespaced-apart. The substrate and the solidified layer are then subjectedto processes to transfer, into the substrate, a relief image thatcorresponds to the pattern in the solidified layer.

It is desirable to provide an improved method of separating a templatefrom a solidified layer.

SUMMARY OF THE INVENTION

The present invention is directed towards a chucking system, including,inter alia, a body having a surface with a pin extending therefromhaving a throughway defined therein, and a land surrounding theprotrusions defining a channel between the pin and the land. In afurther embodiment, the body comprises a plurality of protrusions. Theconfiguration of the chucking system allows varying the chucking force.The present invention is directed towards a method of separating a mold,included in a template, from a solidified layer disposed on a substrate.The method includes, inter alia, applying a separation force to thetemplate to separate the template from the layer; and facilitatinglocalized deformation in the substrate to reduce the magnitude ofseparation force required to achieve separation. It is believed that byreducing the separation forces, damage to the recorded layer may beminimized. It is believed that the present chucking system reduces theseparation forces required and results in minimization of damage to therecorded layer during separation. These embodiments and others aredescribed more fully below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a template in contact with animprinting layer, disposed upon a substrate in accordance with the priorart;

FIG. 2 is a cross-sectional view of a template undergoing separationfrom an imprinting layer, disposed upon a substrate, in accordance withone embodiment of the present invention;

FIG. 3 is a cross-sectional view of a template undergoing separationfrom an imprinting layer, disposed upon a substrate, in accordance witha second embodiment of the present invention;

FIG. 4 is a cross-sectional view of a template mounted to a templateholder in accordance with the present invention;

FIG. 5 is a top down view of a wafer chuck demonstrating a firstembodiment of differing vacuum sections that may be provided inaccordance with the present invention;

FIG. 6 is a top down view of a wafer chuck demonstrating a secondembodiment of differing vacuum sections that may be provided inaccordance with the present invention;

FIG. 7 is a top down view of a wafer chuck demonstrating a thirdembodiment of differing vacuum sections that may be provided inaccordance with the present invention;

FIG. 8 is a side view of the wafer chuck and substrate shown in FIG. 3being subject to a release scheme in accordance with an alternateembodiment;

FIG. 9 is a top down view of one embodiment of the wafer chuck shown inFIG. 2;

FIG. 10 is a cross-sectional view of the wafer chuck shown in FIG. 9taken along lines 10-10;

FIG. 11 is a cross-sectional view of a wafer chuck shown in FIG. 10having a substrate disposed thereon;

FIG. 12 is a cross-sectional view of a second embodiment of the waferchuck, shown in FIG. 2, having a substrate disposed thereon;

FIG. 13 is a cross-sectional view of a template in contact with animprinting layer, disposed upon a substrate, wherein the substrate issubjected to a pushing force;

FIG. 14 is a simplified top down plan view showing a template having aplurality of air nozzles arranged locally to exert a pushing force;

FIG. 15 is a simplified top down plan view showing a template having aplurality of air nozzles arranged as an array to exert a pushing force;

FIG. 16 is a simplified top down plan view showing a template having aplurality of trenches disposed therein to facilitate release of airlocated between a template and an imprinting layer;

FIG. 17 is a side view of a template shown in FIG. 16;

FIG. 18 is a simplified top plan down view showing a template having aplurality of holes disposed therein to facilitate release of air locatedbetween a template and an imprinting layer; and

FIG. 19 is a side down view of the template shown in FIG. 17.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1, a template 10 is shown in contact with animprinting layer 12. Typically, template 10 may be comprised of fusedsilica and imprinting layer 12 may be formed from any material known inthe art. Exemplary compositions for imprinting material 12 are disclosedin U.S. patent application Ser. No. 10/763,885, filed Jan. 24, 2003,entitled Materials and Methods for Imprint Lithography, which isincorporated by reference. Imprinting layer 12 may be positioned on asubstrate 14, with substrate 14 having a thickness ‘t’ associatedtherewith. Substrate 14 may be formed from virtually any materialincluding silicon, fused silica, metal or compound materials typicallyassociated with the manufacture of integrated circuits. Template 10comprises a surface 16 having a plurality of features disposed thereon,with the plurality of features comprising a plurality of protrusions 18and recessions 20. The plurality of protrusions 18 and recessions 20form a pattern to be transferred into imprinting layer 12, forming arelief image therein. More specifically, template 10 contacts imprintinglayer 12 such that the material of imprinting layer 12 ingresses intoand fills the plurality of recessions 20 to form imprinting layer 12with a contiguous structure across surface 16 of template 10, whereintypically the atmosphere surrounding template 10 and imprinting layer 12may be saturated with helium. Template 10 may be connected to an imprinthead 11. The imprint head 11 may be adapted to move along the X-, Y-,and/or Z-axes, thereby generating separation force F_(S) by movingtemplate 10 along the Z-axis away from substrate 14. To that end,substrate 14 typically remains in a fixed position with respect to theZ-axis while imprint head 11 undergoes movement.

Imprinting layer 12 may be formed from a photo-sensitive material suchthat when exposed to an actinic component, the same is polymerized andcross-linked to form a solidified material. The actinic component mayinclude ultraviolet wavelengths, thermal energy, electromagnetic energy,visible light and the like. The actinic component employed is known toone skilled in the art and typically depends on the material from whichimprinting layer 12 is formed.

Solidification of imprinting layer 12 occurs after template 10 makescontact therewith and the imprinting layer 12 fills the plurality ofrecessions 20. Thereafter, template 10 is separated from imprintinglayer 12. In this manner, the relief image is recorded into imprintinglayer 12 with a pattern corresponding to the pattern of template 10.

Separation of template 10 from solidified imprinting layer 12 isachieved by application of a force F_(s), to template 10. The separationforce F_(s), is of sufficient magnitude to overcome adhesion forcesbetween template 10 and solidified imprinting layer 12 and theresistance of substrate 14 to strain (deformation). It is believed thatdeformation of a portion of substrate 14 facilitates separation oftemplate 10 from solidified imprinting layer 12. Wafer chuck 22 mayretain substrate 14 during separation using any number of well knownstraining forces, F_(c), e.g., electrostatic forces, magnetic forces,vacuum forces and the like. As a result, the direction of separationforce F_(s) is typically opposite to that of the direction of thestraining force F_(c). Typically, wafer chuck 22 is supported by a stage23 that facilitates movement along X, Y and/or Z axes. An exemplaryimprint lithography system is sold under the tradename IMPRIO™ 100available from Molecular Imprints, Inc. of Austin, Tex.

As shown in FIG. 1, a magnitude of the strain (deformation) of substrate14 is a function of the separation force F_(s) applied and typicallyresults in the formation of strained region 24 in which substrate 14 isspaced from wafer chuck 22 a distance d. Strained region 24 is typicallygenerated proximate to a region of imprinting layer 12 in contact withtemplate 10, referred to as the processing region.

However, it is desired to minimize the magnitude of the separation forceF_(s) necessary to achieve separation of template 10 and solidifiedimprinting layer 12. For example, minimizing the magnitude of theseparation force F_(s) facilitates alignment processes so that template10 and substrate 14 may be properly aligned, as well as allow anincreased ratio of template patterning area versus total template area.Additionally, minimizing the separation force F_(s) necessary to achieveseparation of template 10 and solidified imprinting layer 12 reduces theprobability of structural comprise of template 10, substrate 14, andsolidified imprinting material 12.

Furthermore, deformation of substrate 14 creates potential energy instrained region 24 that is transformed into kinetic energy uponseparation of template 10 from solidified imprinting layer 12.Specifically, after separation of template 10 from solidified imprintinglayer 12, the separation force F_(s) upon substrate 14 approaches zero.The straining force F_(c) and the elasticity of the material from whichsubstrate 14 is formed causes strained region 24 to accelerate towardchuck 22, such that strained region 24 typically collides with waferchuck 22. It is believed that the collision of strained region 24 withwafer chuck 22 has the deleterious effect of compromising the structuralintegrity of substrate 14 and the solidified imprinting layer 12 formedthereon. This makes problematic, inter alia, alignment between substrate14 and template 10.

Referring to FIG. 2, the present invention attenuates, if not prevents,the aforementioned deleterious effects associated with separation oftemplate 10 from solidified imprinting layer 12. This is achieved byreducing, for a given substrate 14, template 10, and solidifiedimprinting layer 12, the magnitude of the separation force F_(s)necessary to achieve separation between template 10 and solidifiedimprinting layer 12. To that end, wafer chuck 122 is configured tocontrol a magnitude of the strain (deformation) to which substrate 14 issubjected, particularly during separation. Wafer chuck 122 generates astraining force F_(c) from a plurality of independently generated forcesF₁ and F₂. This facilitates providing a straining force F_(c) that mayvary in direction and magnitude across substrate 14. For example, themagnitude of variable forces F₂ may be substantially less than themagnitude of chucking forces F₁. As a result, when template 10 issubjected to a separation force F_(s), chucking forces F₁ may beassociated with a non-strained region 26 of substrate 14, and variableforces F₂ may be associated with strained region 24 of substrate 14.

In this example, forces F₁ and F₂ are both along directionssubstantially opposite to the direction of the separation force Fs.Separation force F_(S) may be generated by movement of an imprintinghead 11 to which template is connected, as discussed above with respectto FIG. 1. Additionally, wafer chuck 122, shown in FIG. 2, may besupported by a stage 23, as discussed above with respect to FIG. 1. Itshould be noted, however, that separation force F_(S) may be generatedby keeping the position of template 10 fixed with respect to the Z-axisand moving substrate 14 along the Z-axis away from template 10 employingstage 23. Alternatively, the separation force F_(S) may result from thecombination of moving template 10 and substrate 14 in oppositedirections along the Z axis. For purposes of the present discussion,however, the invention is discussed with respect to moving imprint head11 so that template 10 moves along the Z axis away from substrate 14,while substrate remains fixed with respect to the Z axis.

It should be noted that the magnitude of forces F₁ and F₂ may havevirtually any value desired, so long as portions of substrate 14 outsideof strained region 24 is retained upon wafer chuck 122 when the same issubjected to separation force Fs. For example, variable forces F₂ mayhave a magnitude approaching zero. As a result of the magnitude ofvariable forces F₂ being substantially less than the magnitude ofchucking forces F₁, the magnitude of the separation force F_(S) requiredto separate template 10 from solidified imprinting layer 12 may bereduced. More specifically, the magnitude of variable forces F₂ areestablished to facilitate strain (deformation) of a portion of substrate14 in superimposition with template 14 in response to separation forceF_(S), referred to as strained region 24.

Referring to FIG. 3, alternatively, straining force F_(c) may be variedacross substrate 14 such that the direction of variable forces F₂ may beopposite to the direction of chucking forces F₁ and commensurate withthe direction of separation force F_(s). The magnitude of the variableforces F₂ may be the same, greater or less than a magnitude of chuckingforces F₁. In this manner, localized deformation of substrate 14 isfacilitated by variable forces F₂ pushing strained region 24 away fromwafer chuck 122. This may or may not be independent of the presence ofseparation force F_(S).

As mentioned above, in the present example chucking forces F₁ functionto hold substrate 14 upon wafer chuck 122 when subjected to separationforce F_(s). As a result of the direction of the variable forces F₂being substantially the same as the direction of the separation forceF_(s), the magnitude of the separation forces F_(s) required to separatetemplate 10 from solidified imprinting layer 12 may be reduced.

Furthermore, as a result of variable forces F₂ being in a directionsubstantially the same as the direction of separation force F_(s), thevariable forces F₂ may reduce the impact, if not avoid collision, ofstrained region 24 with template 10. More specifically, second variableforces F₂ reduce the velocity, and thus, the kinetic energy of strainedregion 24 as the same propagates towards wafer chuck 122, afterseparation of template 10 from solidified imprinting layer 12. In thismanner, strained region 24 comes to rest against wafer chuck 122 withoutunduly compromising the structural integrity of the same.

After separation of template 10 from solidified imprinting layer 12, themagnitude and direction of variable forces F₂ may be changed. Forexample, variable forces F₂ may be provided to have the same magnitudeand direction as chucking forces F₁. Further, the change in magnitudeand direction of variable forces F₂ may vary linearly during a period oftime such that the magnitude of variable forces F₂ having a directionopposite to chucking forces F₁ approaches zero. Upon reaching zerovariable forces F₂ change direction and are slowly increased to becommensurate with the magnitude and direction of chucking forces F₁. Asa result, substrate 14 may be subjected to a gradient of variable forcesF₂ that slowly decelerate strained region 24 and gradually increase tofixedly secure substrate 14 to wafer chuck 122. Therefore, an abruptdeceleration of substrate 14 in response to contact with wafer chuck122, i.e., a collision, may be avoided while minimizing the force ofimpact with wafer chuck 122.

Before separation of template 10 from solidified imprinting layer 12,the direction of the variable forces F₂ may be substantially theopposite as the direction of separation force F_(s), as described abovewith respect to FIG. 2. However, upon separation of template 10 fromsolidified imprinting layer 12, the direction of variable forces F₂ maybe substantially the same as the direction of separation force F_(s), asdescribed above with respect to FIG. 3.

Referring to FIGS. 1 and 4, to further facilitate the separation oftemplate 10 from imprinting layer 12, template 10 may be subjected to abowing force F_(B). More specifically, bowing force F_(B) may be appliedalong a center region 628 of template 10 and along a direction oppositeto that of the direction of the separation force Fs, shown in FIG. 1.The bowing force F_(B) may be applied in conjunction with, orindependent of, varying the magnitude and the direction of the strainingforces Fc, as discussed above. To that end, template 10 may be attachedto a template chuck as disclosed in U.S. patent application Ser. No.10/999,898, filed Nov. 30, 2004, assigned to the assignee of the presentpatent application and having Cherala et al. identified as inventors,which is incorporated by reference herein.

The template chuck includes a body 631 having a centralized throughway633, one side of which is sealed by a fused silicate plate 635 and agasket 636. Surrounding throughway 633 is a recess 637 and gaskets 638.Properly positioning template 10 upon body 631 seals throughway 633forming a chamber, as well as sealing of recess forming a second chambersurrounding the centralized chamber. The centralized chamber and thesecond chamber may each be provided with a desired pressurizationvis-à-vis passageways 640 and 641, respectively. By evacuating thesecond chamber and pressurizing the central chamber, bowing force F_(B)may be applied to template 10 without removing the same from body 631.

Referring to FIGS. 1, 5 and 6, to vary the magnitude and the directionof the straining force F_(c) across substrate 14, the aforementionedwafer chuck 122 may be employed. Furthermore, the following embodimentsmay be employed in step and repeat processes, wherein an exemplary stepand repeat process is disclosed in United States published patentapplication No. 2004/0008334 filed as United patent application Ser. No.10/194,414, assigned to assignee of the present invention andincorporated herein by reference.

To that end, wafer chuck 122 may be configured to provide a plurality ofdiscrete vacuum sections 30 _(A)-30 _(Z). For purposes of the presentinvention, each of the plurality of vacuum sections 30 _(A)-30 _(Z) isdefined as providing one or more chucking forces of common magnitude anddirection, e.g., there may be one straining force, F_(c), associatedwith one of discrete vacuum sections 30 _(A)-30 _(Z) or multiplechucking forces, each of which are substantially identical in directionand magnitude. The number, size and shape of vacuum sections 30 _(A)-30_(Z) may vary dependent upon several factors. Additionally, the size andshape of any one of the plurality of vacuum sections 30 _(A)-30 _(Z) maydiffer from the remaining vacuum sections of the plurality of vacuumsections 30 _(A)-30 _(Z). For example, the size and/or shape of one ormore of the vacuum sections may be commensurate with the size and/orshape of the region 24. As a result, each of the plurality of vacuumsections 30 _(A)-30 _(Z) may be provided with one of a number of shapes,including any polygonal shape, such as the square shape as shown, aswell as circular shapes shown as 130 or annular shapes shown as 230, inFIG. 6. Additionally, vacuum sections may include any one or more ofirregular shapes 330, shown in FIG. 7.

Referring to FIGS. 5-7, although it is possible that each of theplurality of vacuum sections defined on a common wafer chuck 122 have acommon shape and size, it is not necessary. Thus wafer chuck 222 maydefine irregular vacuum sections 330, along with a hexagonal vacuumsection 430, a rectangular vacuum section 530, a circular vacuum section130, and an annular vacuum section 230.

Referring to FIGS. 2, 5, 7 and 8, each of the plurality of vacuumsections 30 _(A)-30 _(Z) may be individually addressed so that differingchucking forces may be associated with the plurality of vacuum sections30 _(A)-30 _(Z). In this manner, the locus of the desired chuckingforces, e.g., F₁ and/or F₂, may be established with great precision. Itis desired, however, to vary the straining forces F_(c) associated withthe plurality of vacuum sections 30 _(A)-30 _(Z) so that substrate 14may be along an axis that extends across the entire area of substrate14. To that end, adjacent rows of said plurality of vacuum sections 30_(A)-30 _(Z) define a straining force differential ΔF_(C). For example,vacuum sections 30 _(D), 30 _(I), 30 _(O), 30 _(U), 30 _(Z), 30 _(J), 30_(P), 30 _(V) may generate variable force F₂, that is lower thanchucking force F₁, generated by the remaining vacuum sections, 30 _(A),30 _(B), 30 _(C), 30 _(E), 30 _(F), 30 _(G), 30 _(H), 30 _(K), 30 _(L),30 _(M), 30 _(N), 30 _(Q), 30 _(R), 30 _(S), 30 _(T), 30 _(W), 30 _(X),and 30 _(Y). This would enable substrate 14 to bend about axis A, whichis facilitated by the force differential ΔF_(C) being defined between afirst row consisting of vacuum sections 30 _(D), 30 _(I), 30 _(O), 30_(U) and 30 _(Z), and a second row consisting of vacuum sections 30_(C), 30 _(H), 30 _(N), 30 _(T) and 30 _(Y).

Referring to FIGS. 9 and 10, to provide wafer chucks 122 and/or 222 withthe aforementioned vacuum characteristics, wafer chuck 122 and 222 areintegrally formed from stainless steel or aluminum with a plurality ofspaced-apart pins 32 and 33, defining a plurality of channels 36therebetween. Although shown as having a circular cross-section, each ofthe plurality of pins 32 and 33 may have virtually any cross-sectionalshape desired, including polygonal shapes and typically have a pitch of3 millimeters. One or more of the plurality of pins are hollow defininga throughway 34 that extends from a passageway 35, terminating in anopening facing substrate 14, as shown in FIG. 11. These are shown aspins 32, with throughway typically having a diameter of approximately 1millimeter to prevent bowing of the portion of substrate 124 insuperimposition therewith.

Although each of pins 32 is shown in fluid communication with a commonpassageway 35, this is not necessary. Rather, throughway 34 of each ofthe plurality of pins 32 may be individually addressable such that thevolume and direction of fluid passing therethrough per unit time isindependent of the fluid flow through throughways 34 associated with theremaining pins 32. This may be achieved by placing one or more of pins32 in fluid communication with a passageway that differs from thepassageways in fluid communication with the remaining pins 32. In afurther embodiment, throughways 34 may comprise a stepped structure. Theplurality of pins 34 may be surrounded by a land 37 upon which substrate14 rests. Channels 36 are typically in fluid communication with a commonpassageway 39 via aperture 40.

Referring to FIGS. 10 and 11, substrate 14 is retained on wafer chuck122 by straining force F_(c) generated by fluid flow through channels 36and/or throughways 34. To that end, passageway 35 is in fluidcommunication with a pressure control system 41 and passageway 39 is influid communication with a pressure control system 43. Both of pressurecontrol systems 41 and 43 are operated under control of processor 45that is in data communication therewith. To that end, processor mayinclude computer readable code operated on by the processor to carryingout the fluid flows mentioned with respect to FIGS. 2-11. Upon beingdisposed upon wafer chuck 122, one surface 47 of substrate 14, facingwafer chuck 122, rests against pins 32 and 33. In the presence of thestraining force F_(c), and the absence of separation force F_(s), an endof throughways 34 facing substrate 14 is substantially sealed,hermetically, by surface 47 resting against pins 32 and 33. No fluidflows between throughways 34 and channels 36 as a result of the seal bysurface 47.

Upon application of separation force F_(s), a portion of surface 47 insuperimposition with solidified imprinting layer 12 becomes separatedfrom pins 32 and/or 33. To facilitate this separation by reducing amagnitude of separation force F_(S) required to achieve the same, pins32 are disposed throughout the area of wafer chuck 122. The fluidflowing through throughways 34 is selected so that variable force F₂ isless than chucking force F₁. Typically, chucking force F₁ is generatedby operating pressure control system 43 at full vacuum. When variableforce F₂ is operated in a pressure state, it is of sufficient magnitudeto generate a pressure of approximately 200 kilo Pascals (kPa) in thevolume disposed between strained region 24 and wafer chuck 122. This isusually creates approximately 10 microns of movement of substrate 14 atstrained region 24. As a result of the seal being broken, throughways 34are placed into fluid communication with passageway 39 via channels 36and apertures 40. This further reduces the magnitude of straining forcesF_(C) in superimposition with strained region 24, thereby reducing theseparation force F_(S) required to separate template 10 from imprintinglayer because strain/deformation of substrate 14 in region 24 isfacilitated.

Referring to FIG. 12, in an alternate embodiment, wafer chuck 322 mayprovide the aforementioned vacuum characteristics, without use of pins32 and 33. To that end, a surface 49 of wafer chuck 322 includes aplurality of apertures 50 and 52 that may be configured to have a flowof fluid therethrough, the magnitude and direction of which may beindependent of the flow of fluid through the remaining apertures 50 and52. Apertures typically have a 3 millimeter pitch and a diameter of 2millimeters, sufficient to reduce the probability of bowing of theportion of substrate 14 in superimposition therewith.

In the present example, apertures 50 are in fluid communication with acommon passageway 53 and apertures 52 are in fluid communication with acommon passageway 55. The straining force F_(c) generated by fluid flowsthrough one or more of the plurality of spaced-apart apertures 50 and52. Before separation, the portion of the plurality of spaced-apartapertures 50 and 52 may have fluid passing therethrough at a first flowrate, 0 sccm or greater. Were separation force F_(s) present, fluid maypass through apertures 50 and 52 at a flow rate that differs from thefirst flow rate. Specifically, the flow rate of fluid passing throughapertures 50 and 52 may vary in response to the presence of separationforce F_(S). Typically the aforementioned change in flow rate islocalized to apertures 50 and 52 in superimposition with strained region24. The change in flow rate is typically sufficient to reduce themagnitude of the straining force F_(c). As such, the change in flow ratetypically affects the fluid passing though only one of apertures 52 orapertures 50. For example, the flow rate through apertures 52, insuperimposition with strained region 24, would change so that thestraining force F_(C) generated thereby is reduced. The flow ratethrough apertures 50 remains substantially constant.

Referring to FIG. 2, to further assist in separation of template 10 fromimprinting layer 12, the imprinting layer may be composed of materialthat produces a gaseous by-product when exposed to predeterminedwavelengths as disclosed in U.S. Pat. No. 6,218,316 which isincorporated by reference herein. The gaseous by-product can producelocalized pressure at the interface between imprinting layer 12 and moldthe flat surface. The localized pressure can facilitate separation oftemplate 10 from imprinting layer 12. The wavelength of radiation thatfacilitates generation of the gaseous by-product may include suchwavelengths as 157 nm, 248 nm, 257 nm and 308 nm, or a combinationthereof. After generation of the gaseous by-product, it is desired toexpeditiously commence separation of template 10 so as to minimizedamage to imprinting layer 12. Further, the gaseous by-product locatedbetween template 10 and imprinting layer 12 may leak out from betweentemplate 10 and imprinting layer 12, which is undesirable. Furthermore,the separation of template 10 from imprinting layer 12 should beorthogonal to imprinting layer 12 to minimize distortions of theimprinting layer 12.

Referring to FIG. 13 to further assist in separation of template 10 fromimprinting layer 12, a pushing force F_(p) may be employed betweentemplate 10 and substrate 14. Specifically, the pushing force F_(p) maybe applied proximate to substrate 14 in areas of substrate 14 not insuperimposition with template 10. The pushing force F_(p) facilitates inseparation of template 10 by moving substrate 14 away from template 10.To that end, pushing force F_(P) is directed along a direction oppositeto separation force F_(S); thereby the magnitude of the separation forceF_(S) required to achieve separation may be reduced. The pushing forceF_(p) may be applied by a plurality of air nozzles 62 arranged locally,as shown in FIG. 14, or as an array 162, as shown in FIG. 15. The gasemployed within the plurality of air nozzles includes, but is notlimited to, nitrogen (N₂). The pushing force F_(p) may be appliedindependent or in conjunction with varying the straining force F_(c), asdiscussed above with respect to FIGS. 2-12.

Referring to FIGS. 2, 16, and 17 to further assist in separation oftemplate 10 from imprinting layer 12, template 10 may comprises aplurality of trenches 38 to decrease the vacuum sealing effect betweentemplate 10 and imprinting layer 12. Trenches 66 facilitate release ofair positioned between template 10 and imprinting layer 12 when template10 and imprinting layer 12 are in contact, thus decreasing the vacuumsealing effect between template 10 and imprinting layer 12. As a result,the magnitude of the separation force F_(s) may be reduced, which isdesired.

Referring to FIGS. 18 and 19, in a further embodiment, template 10 maycomprise a plurality of holes 68, wherein the plurality of holes 68function analogously to trenches 66, such that holes 68 function todecrease the vacuum sealing effect between template 10 and imprintinglayer 12.

The embodiments of the present invention described above are exemplary.Many changes and modifications may be made to the disclosure recitedabove, while remaining within the scope of the invention. The scope ofthe invention should, therefore, be determined not with reference to theabove description, but instead should be determined with reference tothe appended claims along with their full scope of equivalents.

1. A chucking system comprising: a body having a surface with aplurality of pins extending therefrom, defining a plurality of channelstherebetween, a subset of said plurality of pins having a throughwaydefined therein, with said surface having a plurality of aperturesformed therein in superimposition with a subset of said plurality ofchannels; and a land surrounding said pin defining a channel betweensaid pin and said land.
 2. The chucking system as recited in claim 1wherein said surface further includes an aperture formed thereinextending from plurality of apertures are in fluid communication with afirst passageway and in fluid communication therewith, with saidthroughway being said plurality of throughways in fluid communicationwith a second passageway differing from said first passageway.
 3. Thechucking system as recited in claim 1 further including additional pinswith said pin and said additional pins defining a plurality of pins,with wherein each of the pins of a subset of said plurality of pinsincluding includes said throughway defined therein.
 4. The chuckingsystem as recited in claim 1 further including additional pins with saidpin and said additional pins defining a plurality of pins categorizedinto first and second subsets, with each of the pins associated withsaid first subset being wherein an additional subset of said pluralityof pins, differing from said subset, is solid and each of the pinsassociated with said second subset including said throughway.
 5. Thechucking system as recited in claim 1 further including additional pinswith said pin and said additional pins defining a plurality of pinscategorized into first and second subsets, with each of the pinsassociated with said first subset being wherein an additional subset ofsaid plurality of pins, differing from said subset, is solid and each ofthe pins associated with said second subset including said throughwayand said subset of said plurality of pins being in fluid communicationwith a common passageway.
 6. The chucking system as recited in claim 2wherein said surface further includes an aperture formed thereinextending from a first passageway and in fluid communication therewith,with said throughway being in fluid communication with a secondpassageway and further including a first pressure control system influid communication with said first passageway to create a first fluidflow in said channel, and a second pressure control system in fluidcommunication with said second passageway to create a second fluid flowthrough said throughway.
 7. The chucking system as recited in claim 2further including first and second pressure control systems andadditional pins with said pin and said additional pins defining aplurality of pins, with each of the pins associated with a subset ofsaid plurality of pins including said throughway and being in fluidcommunication with a first passageway, with said surface including anaperture in fluid with a second passageway, said a first pressurecontrol system being in fluid communication with said first passagewayto create a first fluid flow in said throughway and a second pressurecontrol system in fluid communication with said second passageway tocreate a second fluid flow through said aperture.
 8. The chucking systemas recited in claim 1 further including a pressure control apparatus andadditional pins with said pin and said additional pins defining aplurality of spaced-apart pins with additional channels being formedtherebetween, with said surrounding said plurality of pins defining saidchannel, with said channel and said additional channels defining aplurality of channels, said pressure control apparatus being in fluidcommunication with said channels and said plurality of pins to providesaid wafer chuck chucking system with a plurality of vacuum sectionshaving predetermined shapes.
 9. The chucking system as recited in claim1 wherein each pin of said subset of said plurality of pins having athroughway defined therein is a hollow pin, where said throughway isdefined through a hollow section of each pin.
 10. A chucking systemcomprising: a body having a surface with a plurality of pins extendingtherefrom, defining a plurality of channels therebetween, a subset ofsaid plurality of pins having a throughway defined therein, with saidsurface having a plurality of apertures formed therein insuperimposition with a subset of said plurality of channels, with saidplurality of apertures being in fluid communication with a firstpassageway and said plurality of throughways being in fluidcommunication with a second passageway; and, a pressure controlapparatus in fluid communication with said first and second passagewaysto create flows of fluid through said plurality of apertures andthroughways with the characteristics of said fluid flow through saidplurality of apertures differing from the characteristics of said flowsof fluid through said plurality of throughways to provide said surfacewith differing chucking forces over an area of said surface.
 11. Thechucking system as recited in claim 10 wherein said plurality ofapertures and throughways are arranged over said area to provide saidwafer chuck with a plurality of vacuum sections having a shape selectedfrom a set of shapes consisting essentially of polygonal and circularshapes.
 12. The chucking system as recited in claim 10 wherein each pinof said subset of said plurality of pins having a throughway definedtherein is a hollow pin, where said throughway is defined through ahollow section of each pin.
 13. A chucking system comprising: a bodyhaving an aperture formed therein with a plurality of spaced-apart pinsextending from said surface, with each of the pins associated with afirst subset being solid and each of the pins associated with a secondsubset including a throughway and being in fluid communication with afirst passageway, with said surface having a plurality of aperturesformed therein in fluid communication with a second passageway, with aplurality of channels being defined between said plurality of pins; afirst pressure control system in fluid communication with said firstpassageway; and a second pressure control system in fluid communicationwith said second passageway, with said first and second pressure controlsystems configured to create flows of fluid through said plurality ofthroughways and said plurality of apertures to provide differingchucking forces over an area of said surface.
 14. The chucking system asrecited in claim 13 wherein said plurality of pins are arranged oversaid surface to provide said chucking system with a plurality of vacuumsections having predetermined shapes in response to said flows of fluid.15. The chucking system as recited 14 wherein said shapes are selectedfrom a set consisting essentially of annular, polygonal and circular.16. The chucking system as recited in claim 13 where said fluid flowsare established so that fluid communication between said throughway andeach of said plurality of channels ceases in response to a substrateresting upon one of said plurality of pins associated with saidthroughway.
 17. The chucking system as recited in claim 13 wherein saidflows of fluid associated with said throughway move in a directionopposite to said flows of fluid through said plurality of apertures. 18.The chucking system as recited in claim 13, wherein each pin of saidsecond subset is a hollow pin, where said throughway is defined througha hollow section of each pin.